XML Suppress Keytip Auto-Assignment in Custom Ribbon Tab
 

I have a custom ribbon tab with several buttons and menus. I would like to
suppress the auto-assignment of a keytip (letters that appear when you hit
Alt button) for the buttons that are sharing the same level as my menus.

I notice there are built in controls that I have used that do not have a
keytip associated with them. How do you suppress or assign a null keytip for
a custom button?